Hi,
Adobe also have a guide for improving performance here...http://www.adobe.com/devnet/livecycle/articles/DynamicInteractiveFormPerformance.pdf
One tip we got was that all of the calculate events fire when the form opens and is re-laid / re-rendered. We "try" to have calculations on the exit event rather than the calculate event, on the basis that the exit event is not processed until the user exits that field.
It would be interesting to hear views on this.
Good luck,
Niall